Apparatus and method for acquisition of on-demand system information in wireless communications

ABSTRACT

A wireless terminal communicates over a radio interface with an access node of a radio access network (RAN), and method of operating same. The wireless terminal comprises receiver circuitry, processor circuitry, and transmitter circuitry. The processor circuitry is configured to initiate a first type system information block (SIB) acquisition process to receive a first type SIB. The first type SIB comprises scheduling information of a system information (SI) message, the SI message comprising at least one second type SIB, and an indication of broadcast status for the SI message, the indication indicating on-demand delivery. The receiver circuitry is configured to receive the first type SIB. The transmitter circuitry configured to transmit an SI request message to request the SI message. The processor circuitry is further configured to initiate an SI message acquisition process to receive the SI message and, in a case that a stored version of one of the at least one second type SIB is not valid, the first type SIB acquisition process is initiated upon a failure of the SI message acquisition process.

This application is a continuation of PCT application PCT/US2019/031669,filed 2019 May 10, and claims the priority and benefit of U.S.provisional application 62/669,838, filed May 10, 2018, both of whichare entitled “APPARATUS AND METHOD FOR ACQUISITION OF ON-DEMAND SYSTEMINFORMATION IN WIRELESS COMMUNICATIONS” and both of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD

The technology relates to wireless communications, and particularly tomethods, apparatus, and techniques for requesting, transmitting,updating, and using system information (SI) in wireless communications.

BACKGROUND

In wireless communication systems, a radio access network generallycomprises one or more access nodes (such as a base station) whichcommunicate on radio channels over a radio or air interface with pluralwireless terminals. In some technologies such a wireless terminal isalso called a User Equipment (UE). A group known as the 3rd GenerationPartnership Project (“3GPP”) has undertaken to define globallyapplicable technical specifications and technical reports for presentand future generation wireless communication systems. The 3GPP Long TermEvolution (“LTE”) and 3GPP LTE Advanced (LTE-A) are projects to improvean earlier Universal Mobile Telecommunications System (“UMTS”) mobilephone or device standard in a manner to cope with future requirements.

In typical cellular mobile communication systems, the base stationbroadcasts on the radio channels certain information which is requiredfor mobile stations to access to the network. In Long-Term Evolution(LTE) and LTE Advanced (LTE-A), such information is called “systeminformation” (“SI”). Each access node, such as an evolved NodeB (“eNB”)or a gNB in the 5G New Radio (NR) System, broadcasts such systeminformation to its coverage area via a Master Information Block (MIB)and several System Information Blocks (SIBs) on downlink radio resourcesallocated to the access node.

A wireless terminal (“UE”), after entering a coverage area of an eNB orgNB, is required to obtain all the MIB/SIBs which are necessary toaccess to the system. For sake of UEs under coverage, the eNB or gNBperiodically broadcasts all MIB/SIBs relevant for offered services,where each type of MIB or SIBs is transmitted in a designated radioresource(s) with its own pre-determined/configurable frequency.

This all-broadcast-based periodic delivery method (e.g., collectivebroadcast of all SIBs, not just those necessary for system access) isefficient under a condition where many UEs are almost always flowinginto the coverage area (such as a macro cell). However, this approachmay result in wasting valuable radio resources in case of small celldeployment. Therefore, more efficient methods of SIB transmission aredesired.

What is needed, therefore, and an example object of the technologydisclosed herein, are methods, apparatus, and techniques for obtainingand/or updating SIBs in/of Other SI (Other SI SIBs), and also for makinga determination of SI message acquisition process failure and remedialprocesses therefor.

SUMMARY

In one of its example aspects the technology disclosed herein concerns awireless terminal which communicates over a radio interface with anaccess node of a radio access network (RAN), and method of operatingsame. In an example basic embodiment the wireless terminal comprisesreceiver circuitry, processor circuitry, and transmitter circuitry. Theprocessor circuitry is configured to initiate a first type systeminformation block (SIB) acquisition process to receive a first type SIB.The first type SIB comprises scheduling information of a systeminformation (SI) message, the SI message comprising at least one secondtype SIB, and an indication of broadcast status for the SI message, theindication indicating on-demand delivery. The receiver circuitry isconfigured to receive the first type SIB. The transmitter circuitryconfigured to transmit an SI request message to request the SI message.The processor circuitry is further configured to initiate an SI messageacquisition process to receive the SI message and, in a case that astored version of one of the at least one second type SIB is not valid,the first type SIB acquisition process is initiated upon a failure ofthe SI message acquisition process.

In another of its example aspects the technology disclosed hereinconcerns base station apparatus which communicates over a radiointerface with a user equipment. The base station apparatus comprisestransmitter circuitry, receiver circuitry, and processor circuitry. Thetransmitter circuitry is configured to transmit a first type systeminformation block (SIB). The first type SIB comprises schedulinginformation of a system information (SI) message, the SI messagecomprising at least one second type SIB, and an indication of broadcaststatus for the SI message, the indication indicating on-demand delivery.The receiver circuitry is configured to receive an SI request message torequest the SI message. The processor circuitry is configured to use thetransmitter circuitry to deliver the SI message. The first type SIB isre-acquired by the user equipment upon the user equipment failing on anSI message acquisition process to receive the SI message, in a case thata version of one of the at least one second type SIB stored in the userequipment is not valid.

In another of its example aspects the technology disclosed hereinconcerns a method in a wireless terminal which communicates over a radiointerface with an access node of a radio access network (RAN). In anexample basic mode the method comprises: initiating a first type systeminformation block (SIB) acquisition process to receive a first type SIB;receiving the first type SIB; transmitting a system information (SI)request message to request an SI message; and initiating an SI messageacquisition process to receive the SI message. The first type SIBcomprises scheduling information of the SI message and an indication ofbroadcast status for the SI message, the indication indicating on-demanddelivery. The SI message comprises at least one second type SIB. Thefirst type SIB acquisition process is initiated upon a failure of the SImessage acquisition process, in a case that a stored version of one ofthe at least one second type SIB is not valid.

In yet another of its example aspects the technology disclosed hereinconcerns a method in an access node of a radio access network (RAN) thatcommunicates over a radio interface with a wireless terminal or userequipment. In an example basic mode the method comprises: transmitting afirst type system information block (SIB); receiving a systeminformation (SI) request message to request an SI message; anddelivering the SI message. The first type SIB comprises schedulinginformation of the SI message and an indication of broadcast status forthe SI message, the indication indicating on-demand delivery. The SImessage comprises at least one second type SIB. The first type SIB isre-acquired by the user equipment upon the user equipment failing on anSI message acquisition process to receive the SI message, in a case thata version of one of the at least one second type SIB stored in the userequipment is not valid.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and advantages of thetechnology disclosed herein will be apparent from the following moreparticular description of preferred embodiments as illustrated in theaccompanying drawings in which reference characters refer to the sameparts throughout the various views. The drawings are not necessarily toscale, emphasis instead being placed upon illustrating the principles ofthe technology disclosed herein.

FIG. 1 is a diagrammatic view showing transition states of a RadioResource Control RRC state machine.

FIG. 2 is a schematic view showing an example generic communicationssystem comprising a radio access node and a wireless terminal, whereinthe wireless terminal requests, and the radio access node provides,Other system information (Other SI) when the wireless terminal is in aRRC_CONNECTED state.

FIG. 3 is a flowchart showing example, basic example acts or stepsperformed by a wireless terminal of the example generic communicationssystem of FIG. 2.

FIG. 4-FIG. 7 are diagrammatic views illustrating differing exampleformats of a system information block (SIB) which comprises Minimal SIand which carries availability of Other system information (Other SI).

FIG. 8 is a diagrammatic view illustrating an exemplary message flow ofon-demand based SI acquisition procedure.

FIG. 9A, FIG. 9B and FIG. 9C are diagrammatic views illustrating threeoptions for an SI request procedure.

FIG. 10 is a diagrammatic view showing, e.g., a SystemInformationRequestmessage wherein a siRequest information element comprises a bit map.

FIG. 11 is a diagrammatic view illustrating an exemplary message flow ofperiodic broadcast based SI acquisition procedure.

FIG. 12 is a schematic view showing an example generic communicationssystem comprising a wireless terminal configured to detect failure of aSI reception process involving an on-demand SI message, following asuccessful completion of an SI request.

FIG. 13A-FIG. 13D are diagrammatic view of differing implementations ofSIB1 which comprise termination condition parameters.

FIG. 14 is a diagrammatic view illustrating an exemplary message flowincluding an on-demand based SI acquisition procedure which fails.

FIG. 15 is a flowchart showing basic, representative, example acts orsteps performed by the wireless terminal of FIG. 12.

FIG. 16 is a flowchart showing basic, representative, example acts orsteps performed by the access node of FIG. 12.

FIG. 17A is a diagrammatic view of a system information acquisitionfailure detector which comprises a SI window counter for making adetermination of SI message acquisition process termination.

FIG. 17B is a diagrammatic view of a system information acquisitionfailure detector which comprises a SI message acquisition process timerfor making a determination of SI message acquisition processtermination.

FIG. 18A is a diagrammatic view showing a common termination conditionfor plural SI messages.

FIG. 18B is a diagrammatic view showing different termination conditionsfor different SI messages.

FIG. 19 is a schematic view showing an example generic communicationssystem comprising a wireless terminal configured to detect failure of aSI reception process involving a periodically broadcasted SI message.

FIG. 20 is a diagrammatic view illustrating an exemplary message flowincluding a failed SI acquisition procedure for a periodicallybroadcasted SI message.

FIG. 21 is a flowchart showing basic, representative, example acts orsteps performed by the wireless terminal of FIG. 19.

FIG. 22 is a flowchart showing basic, representative, example acts orsteps performed by the access node of FIG. 19.

FIG. 23 is a diagrammatic view showing example electronic machinerywhich may comprise node electronic machinery or terminal electronicmachinery.

DETAILED DESCRIPTION

In the following description, for purposes of explanation and notlimitation, specific details are set forth such as particulararchitectures, interfaces, techniques, etc. in order to provide athorough understanding of the technology disclosed herein. However, itwill be apparent to those skilled in the art that the technologydisclosed herein may be practiced in other embodiments that depart fromthese specific details. That is, those skilled in the art will be ableto devise various arrangements which, although not explicitly describedor shown herein, embody the principles of the technology disclosedherein and are included within its spirit and scope. In some instances,detailed descriptions of well-known devices, circuits, and methods areomitted so as not to obscure the description of the technology disclosedherein with unnecessary detail. All statements herein recitingprinciples, aspects, and embodiments of the technology disclosed herein,as well as specific examples thereof, are intended to encompass bothstructural and functional equivalents thereof. Additionally, it isintended that such equivalents include both currently known equivalentsas well as equivalents developed in the future, i.e., any elementsdeveloped that perform the same function, regardless of structure.

Thus, for example, it will be appreciated by those skilled in the artthat block diagrams herein can represent conceptual views ofillustrative circuitry or other functional units embodying theprinciples of the technology. Similarly, it will be appreciated that anyflow charts, state transition diagrams, pseudocode, and the likerepresent various processes which may be substantially represented incomputer readable medium and so executed by a computer or processor,whether or not such computer or processor is explicitly shown.

As used herein, the term “core network” can refer to a device, group ofdevices, or sub-system in a telecommunication network that providesservices to users of the telecommunications network. Examples ofservices provided by a core network include aggregation, authentication,call switching, service invocation, gateways to other networks, etc.

As used herein, the term “wireless terminal” can refer to any electronicdevice used to communicate voice and/or data via a telecommunicationssystem, such as (but not limited to) a cellular network. Otherterminology used to refer to wireless terminals and non-limitingexamples of such devices can include user equipment terminal, UE, mobilestation, mobile device, access terminal, subscriber station, mobileterminal, remote station, user terminal, terminal, subscriber unit,cellular phones, smart phones, personal digital assistants (“PDAs”),laptop computers, netbooks, e-readers, wireless modems, etc.

As used herein, the term “access node”, “node”, or “base station” canrefer to any device or group of devices that facilitates wirelesscommunication or otherwise provides an interface between a wirelessterminal and a telecommunications system. A non-limiting example of abase station can include, in the 3GPP specification, a Node B (“NB”), anenhanced Node B (“eNB”), a home eNB (“HeNB”), a 5G (New Radio [NR]) gNB,or some other similar terminology. Another non-limiting example of abase station is an access point. An access point may be an electronicdevice that provides access for wireless terminal to a data network,such as (but not limited to) a Local Area Network (“LAN”), Wide AreaNetwork (“WAN”), the Internet, etc. Although some examples of thesystems and methods disclosed herein may be described in relation togiven standards (e.g., 3GPP Releases 8, 9, 10, 11, 12, or higher), thescope of the present disclosure should not be limited in this regard. Atleast some aspects of the systems and methods disclosed herein may beutilized in other types of wireless communication systems.

As used herein, the term “telecommunication system” or “communicationssystem” can refer to any network of devices used to transmitinformation. A non-limiting example of a telecommunication system is acellular network or other wireless communication system.

As used herein, the term “cellular network” can refer to a networkdistributed over cells, each cell served by at least one fixed-locationtransceiver, such as a base station. A “cell” may be any communicationchannel that is specified by standardization or regulatory bodies to beused for International Mobile Telecommunications-Advanced(“IMTAdvanced”). All or a subset of the cell may be adopted by 3GPP aslicensed bands (e.g., frequency band) to be used for communicationbetween a base station, such as a Node B, and a UE terminal. A cellularnetwork using licensed frequency bands can include configured cells.Configured cells can include cells of which a UE terminal is aware andin which it is allowed by a base station to transmit or receiveinformation.

As used herein, “system information” (“SI”) may include a MasterInformation Block (MIB) and several System Information Blocks (SIBs)which are provided on downlink radio resources allocated to an accessnode. The system information may be broadcast, and some types of systeminformation may be provided on demand, e.g., upon receipt of a requestfor system information from a wireless terminal.

In various aspects of the technology disclosed herein, systeminformation is classified into plural categories or types. In an exampleembodiment and mode, a first type of the system information is MinimumSystem Information (Minimum SI), minimally containing informationrequired for UEs initially access to the network, periodicallybroadcasted by each access node (e.g. eNB for LTE, gNB for 5G RadioSystem). In some configurations, Minimum System SI may consist of MIBand a limited number of SIBs. The MIB may contain essential informationfor the radio system to help wireless terminals to synchronize to theserving access node and may also contain instruction how to obtain atleast one of the essential SIBs. The Minimum SI may be also referred as“essential SI”, or first type system information.

A second type of system information, e.g., “Other system information,“Other SI”, or second type system information contains all the othertypes of information, i.e., all types of system information except theMinimum System Information. The Other SI may comprise several systeminformation blocks (SIBs) that are not categorized as Minimum SI. TheOther SI may be also referred as “non-essential SI”. However, the secondtype system information is not to be confused with SIB Type 2, which isa particular (second) system information block (SIB) that may beincluded in the Minimum System Information or may be a part of the OtherSI.

In some example embodiment and modes described herein, for each of theSIBs the access node may choose to broadcast the SIB periodically,similar to the SIBs in Minimum SI. Alternatively, the access node maychoose to refrain from transmitting the SIB until receiving a request ofon-demand delivery from a UE. In this case, the access node mayadvertise the availability of on-demand delivery using Minimum SI.

As described herein, both an access node and a wireless terminal maymanage respective Radio Resource Control (RRC) state machines. The RRCstate machines transition between several RRC states including RRC_IDLE,RRC_INACTIVE and RRC_CONNECTED. FIG. 1 depicts the state transitiondiagram of the RRC states. From the vantage point of a wireless terminale.g., user equipment (UE), the RRC states may be briefly characterizedas follows:

RRC_IDLE:

-   -   A UE specific DRX (discontinuous reception) may be configured by        upper layers;    -   UE controlled mobility based on network configuration;    -   The UE:        -   Monitors a Paging channel;        -   Performs neighboring cell measurements and cell            (re-)selection;        -   Acquires system information.            RRC_INACTIVE:    -   A UE specific DRX may be configured by upper layers or by RRC        layer;    -   UE controlled mobility based on network configuration;    -   The UE stores the Access Stratum (AS) context;    -   The UE:        -   Monitors a Paging channel;        -   Performs neighboring cell measurements and cell            (re-)selection;        -   Performs RAN-based notification area updates when moving            outside the RAN-based notification area;        -   Acquires system information.            RRC_CONNECTED:    -   The UE stores the AS context.    -   Transfer of unicast data to/from UE.    -   At lower layers, the UE may be configured with a UE specific        DRX;    -   Network controlled mobility, i.e. handover within NR and to/from        E-UTRAN;    -   The UE:        -   Monitors a Paging channel;        -   Monitors control channels associated with the shared data            channel to determine if data is scheduled for it;        -   Provides channel quality and feedback information;        -   Performs neighboring cell measurements and measurement            reporting;        -   Acquires system information.

The technology disclosed herein concerns, e.g., apparatus, methods, andprocedures for obtaining and/or updating SIBs in/of Other SI (Other SISIBs), and also includes making a determination of SI messageacquisition process failure and remedial processes therefor.

FIG. 2 shows an example communications system 20 wherein radio accessnode 22 communicates over air or radio interface 24 (e.g., Uu interface)with wireless terminal 26. As mentioned above, the radio access node 22may be any suitable node for communicating with the wireless terminal26, such as a base station node, or eNodeB (“eNB”) or gNB, for example.The node 22 comprises node processor circuitry (“node processor 30”) andnode transceiver circuitry 32. The node transceiver circuitry 32typically comprises node transmitter circuitry 34 and node receivercircuitry 36, which are also called node transmitter and node receiver,respectively.

The wireless terminal 26 comprises terminal processor 40 and terminaltransceiver circuitry 42. The terminal transceiver circuitry 42typically comprises terminal transmitter circuitry 44 and terminalreceiver circuitry 46, which are also called terminal transmitter 44 andterminal receiver 46, respectively. The wireless terminal 26 alsotypically comprises user interface 48. The terminal user interface 48may serve for both user input and output operations, and may comprise(for example) a screen such as a touch screen that can both displayinformation to the user and receive information entered by the user. Theuser interface 48 may also include other types of devices, such as aspeaker, a microphone, or a haptic feedback device, for example.

For both the radio access node 22 and radio interface 24, the respectivetransceiver circuitries 22 include antenna(s). The transmitter circuit34 and transmitter circuit 44 may comprise, e.g., amplifier(s),modulation circuitry and other conventional transmission equipment. Thereceiver circuit 36 and receiver circuit 46 may comprise, e.g., e.g.,amplifiers, demodulation circuitry, and other conventional receiverequipment.

In general operation, access node, 22 and wireless terminal 26communicate with each other across radio interface 24 using predefinedconfigurations of information. By way of non-limiting example, the radioaccess node 22 and wireless terminal 26 may communicate over radiointerface 24 using “frames” of information that may be configured toinclude various channels. In Long Term Evolution (LTE), for example, aframe, which may have both downlink portion(s) and uplink portion(s),may comprise plural subframes, with each LTE subframe in turn beingdivided into two slots. The frame may be conceptualized as a resourcegrid (a two dimensional grid) comprised of resource elements (RE). Eachcolumn of the two dimensional grid represents a symbol (e.g., an OFDMsymbol on downlink (DL) from node to wireless terminal; an SC-FDMAsymbol in an uplink (UL) frame from wireless terminal to node). Each rowof the grid represents a subcarrier. The frame and subframe structureserves only as an example of a technique of formatting of informationthat is to be transmitted over a radio or air interface. It should beunderstood that “frame” and “subframe” may be utilized interchangeablyor may include or be realized by other units of information formatting,and as such may bear other terminology (such as blocks, for example).

To cater to the transmission of information between radio access node 22and wireless terminal 26 over radio interface 24, the node processor 30and terminal processor 40 of FIG. 2 are shown as comprising respectiveinformation handlers. For an example implementation in which theinformation is communicated via frames, the information handler forradio access node 22 is shown as node frame/signal scheduler/handler 50,while the information handler for wireless terminal 26 is shown asterminal frame/signal handler 52.

The node processor 30 of radio access node 22 also includes systeminformation (SI) generator 54. As described above, at least some of thesystem information generated and provided by the system information (SI)generator 54 is Minimum System Information (Minimum SI), also known asfirst type system information, represented by Minimum SI handler 54M.Some of the system information may be Other system information (OtherSI), also known as second type system information, represented by OtherSI handler 540 in FIG. 2. The wireless terminal 26 uses the systeminformation (SI) generated by radio access node 22. Some of the MinimumSI may inform the wireless terminal 26 of the availability of the OtherIS.

FIG. 2 illustrates a generic message 2-1 by which the node radioresource controller 54 may supply the Minimal SI to wireless terminal26. In some example implementations, upon knowing of the availability ofthe Other SI, due to the message 2-1, for example, the wireless terminal26 specifically requests the Other system information, in on-demandfashion, as described herein. The terminal processor 40 of wirelessterminal 26 comprises, e.g., SI processor 56, to facilitate obtainingand use of system information.

The technology disclosed herein concerns, e.g., apparatus, methods, andprocedures for obtaining and/or updating system information blocks(SIBs) in/of the Other SI (Other SI SIBs) in on-demand basis. Since inat least some of the example embodiments and modes the technologydisclosed herein involves the Radio Resource Control (RRC) procedures,FIG. 2 shows terminal processor 40 as comprising node radio resourcecontrol (RRC) controller 60, e.g., node RRC controller 60. The node RRCcontroller 60 may execute an instance of the RRC state machine for eachwireless terminal in which the access node 20 is in communication, witheach instance keeping track of the RRC state transitions experienced bythe wireless terminal associated with the respective instance.

FIG. 2 also shows the terminal processor 40 of wireless terminal 26 ascomprising, in addition to terminal SI processor 56, a terminal RRCcontroller 70. The terminal RRC controller 70 includes or executes theRRC state machine discussed above, which transitions through the RRCstates, as described above and shown in FIG. 2, for a communicationinvolving wireless terminal 26.

FIG. 2 thus shows that the access node 22 comprises node processor 30,e.g., node processor circuitry 30, transmitter circuit 34, and, receivercircuit 36. The transmitter circuit 34 is configured to transmit thefirst type system information over a radio interface, the first typesystem information including availability of a SI message belonging tothe second type system information. The receiver circuit 36 isconfigured to receive from the wireless terminal a request message torequest delivery of the SI message which is available by on-demandbasis. The transmitter circuit 34 is further configured to transmit theSI message to the wireless terminal.

FIG. 2 thus shows that the wireless terminal 26 communicates over radiointerface 24 with access nodes, such as access node 22, of a radioaccess network (RAN). The wireless terminal 26 comprises receivercircuit 46, transmitter circuit 44, and terminal processor 40, e.g.,terminal processor circuitry. The receiver circuit 46 is configured toreceive first type system information over the radio interface. Theterminal processor circuitry is configured to generate a request messageto request the second type SIB which is available in an on-demand basis.The transmitter circuit 44 is configured to transmit the request messageover the radio interface while in the connected state. The receivercircuit 46 is also configured to receive the SI message while in theconnected state.

FIG. 3 shows example, representative acts or steps performed inconjunction with a generic method of operating a wireless terminal of aradio access network (RAN), such as wireless terminal 26 of FIG. 2. Act3-1 comprises the wireless terminal acquiring, e.g., receiving, theMinimum SI that is broadcasted from the currently serving access node,e.g., access node 22. The Minimum SI may be broadcast in a message suchas message 2-1 of FIG. 2. The Minimum SI may contain information aboutthe Other SI, including the delivery method, e.g., periodicbroadcast/on-demand, scheduling information, validity information, etc.Based on the information, the wireless terminal in act 3-2 may determinewhich SI message(s) to acquire by on-demand. As act 3-3, the wirelessterminal may send a request message (depicted as message 2-2 of FIG. 2)to the access node, the request message indicating the SI message(s)that the wireless terminal desires to obtain. As act 3-4 the wirelessterminal 26 may attempt to receive the requested SI message(s) which,e.g., was sent using message 2-3 of FIG. 2.

It was mentioned above that the first type system information includesavailability of a SI message belonging to the second type systeminformation, that the request message requests delivery of a SI messagewhich is available by on-demand basis, and that the SI message istransmitted to the wireless terminal. It should be understood thatreference herein to “a SI message belonging to the second type systeminformation” means one or more pieces of Other system information (OtherSI), e.g., one or more SI messages belonging to the second type systeminformation. In some example situations indeed only one SI message maybe advertised as available and accordingly periodically broadcasted orrequested on-demand. But in other example situations plural SI messages(e.g., plural pieces of Other SI) are advertised as available, some ofwhich may be periodically broadcasted and the others may be requestedon-demand. Furthermore, it should be noted that in some configurations(e.g. the configuration presented in FIG. 7, or in FIG. 13A-D) theavailability may be included in the scheduling information (e.g.schedulingInfoList described below).

In some configurations, the availability and delivery method informationfor Other SI SIBs may be included in SIB Type 1, one of the SIBs in theMinimum SI. FIG. 4 shows an example format of SIB Type 1, includingschedulingInfoList, si-WindowLength, otherSIBInfoList, validity areaidentification (si-AreaID), and possibly other configuration parameters.The otherSIBInfoList is a list of otherSIBInfo, which comprisesSIB-Type, an identifier of a SIB, validityInfo and validity informationof the SIB (a value tag [valueTag], and other parameters, such asvalidity timer, etc.).

SIBs other than SIB1 are carried in SystemInformation (SI) messages andmapping of SIBs to SI messages is flexibly configurable byschedulingInfoList included in SIB1, with restrictions that: each SIB iscontained only in a single SI message, only SIBs having the samescheduling requirement (periodicity given by si-periodicity) can bemapped to the same SI message. There may be multiple SI messagestransmitted with the same periodicity.

In one configuration, each element, schedulingInfo, ofschedulingInfoList may represent one SI message, comprising itsperiodicity (si-Periodicity), delivery method (deliveryMethod)indicating if this SIB is periodically broadcasted or to be transmittedupon request (on-demand), and associated SIB types (one or moreSIB-Type's). The actual broadcast opportunity, e.g., timing/resources,of a given SI message may be determined by a pre-determined or anetwork-configured formula as a function of at least the correspondingperiodicity. At each opportunity the broadcast of the SI message mayoccur within the duration of the window length (si-WindowLength).Hereafter a broadcast opportunity is also referred as a SI window. Morethan one SIB may be possibly transmitted on a same SI window.

In the configuration of FIG. 4 si-AreaID is common for all SI messagesor SIB types, which means that all SIBs have the same validity area.Alternatively, in another configuration, each SI message may have adesignated validity area. FIG. 5 shows an example format of SIB1 forsuch a configuration wherein each SI message may have a designatedvalidity area. Furthermore, in another configuration, having an exampleformat such as shown in FIG. 6, each SIB type may have a designatedvalidity area. Thus, in differing implementations, the systeminformation (SI) generator 54 of FIG. 2, working with node frame/signalscheduler/handler 50, generates the differing formatted SI messages ofFIG. 4, FIG. 5, and FIG. 6, for transmission by node transmittercircuitry 34 over radio interface 24.

FIG. 7 is an alternative format for SIB1, which is logically equivalentto the format shown in FIG. 4. The si-BroadcastStatus informationelement of FIG. 7 may be functionally identical to deliveryModeinformation element described earlier. In one configuration, theinformation element sibValueTagList may comprise a list of value tagsfor the available SIBs included in schedulingInfoList, in the order ofthe SIB numbering scheme (e.g. SIB2, SIB3, SIB4, SIB5, . . . ). Inanother configuration, sibValueTagList may comprise a list of value tagsfor the available SIBs (included in schedulingInfoList) as well as thenon-available SIBs (not included in schedulingInfoList), in the order ofthe SIB numbering scheme (e.g. SIB2, SIB3, SIB4, SIB5, . . . ). In thiscase, a pre-determined value may be set to the value tag for anon-available SIB. Accordingly, the si-BroadcastStatus informationelement may be used for indicating broadcast status (e.g. the broadcaststatus being either periodic broadcast or on-demand basis).

FIG. 8 is an exemplary message flow diagram of on-demand based SIacquisition procedure. As shown by act 8-0, wireless terminal 26 ineither RRC_IDLE, RRC_INACTIVE or RRC_CONNECTED state stores the contentof SIB # A with the validity information, valueTag=a, si-AreaID=2, whichthe wireless terminal has previously received. From the currentlyserving access node, as act 8-1 the wireless terminal may obtain SIB1 asMinimum SI. As shown in FIG. 4, FIG. 5, FIG. 6, and FIG. 7, the SIB1includes the scheduleInfoList, which in turn may include one or moreschedulingInfo information elements. An example scheduleInfoList forthis scenario is shown in Table 1, wherein the k'th schedulingInfoindicates that the SI message associated with this schedulingInfo (SI #k, hereafter), containing SIB # A, will be available by on-demanddelivery. Furthermore, the otherSIBInfo corresponding to SIB # Aindicates that the validity information of SIB # A is valueTag=b,si-AreaID=3. It is assumed hereafter that whenever the wireless terminalreceives SIB1, it has already received MIB beforehand.

TABLE 1 ... schedulingInfoList {   ...   k'th schdulingInfo (SI#k) {    ...     deliveryMethod = on-demand     SIB-type = A     ...   }  ...   } } ... otherSIBInfoList {   ...   otherISBInfo {     SIB-type =A     ValidityInfo {       valueTag = b       ...     }     ...   }  ... } ... si-AreaID = 3 ...

Knowing that the stored SIB # A is now invalid, the wireless terminalmay decide to obtain a valid version of SIB # A, and may initiate the SIrequest procedure represented by act 8-2 and explained herein. After theSI request procedure has a successful result, the wireless terminal maystart the SI reception procedure, shown generally as act 8-3 in FIG. 8.In the SI reception procedure the wireless terminal monitors signalsfrom the access node in the designated SI windows derived from thescheduling information (scheduleInfo) in the SIB1, and thereby attemptsto receive the requested SI # k. The SI windows are shown by dottedrectangles in FIG. 8. FIG. 8 shows by act 8-3 a a first transmission ofthe requested SI # k, which is unsuccessful, and by act 8-3 b a secondtransmission of the requested SI # k, which is successful. A tail of avertical down-pointing arrow in the SI reception procedure depiction ofFIG. 8 is associated with start of the SI reception procedure, while thehead of the same vertical down-pointing arrow is associated with end ofthe SI reception procedure (at successful reception of the SI # k). FIG.8 also shows by act 8-4 that other transmissions of the requested systeminformation may also be made even after the wireless terminal hassuccessfully received the sought SI # k.

In one configuration, the wireless terminal may use a counter, which isincremented at every SI window of a particular SI message, e.g. SI # k.In this configuration, the SI reception procedure may end when therequested SI message(s) are successfully received, or when the counterreaches a maximum counter value. In another configuration the wirelessterminal starts a timer at the beginning of the SI reception procedure.In this configuration, the SI reception procedure may end when therequested SI message(s) are successfully received, or when the timerexpires. The maximum counter value, or the timer value, which may becommon for all SI messages or per-SI message basis, may bepre-configured or configured by network via system information. Theconditions for the wireless terminal to end the SI reception process isreferred as “termination conditions” herein.

FIG. 9A, FIG. 9B and FIG. 9C show three options for the SI requestprocedure. In FIG. 9A, which may be applicable to wireless terminals inany of the RRC states, the request of on-demand delivery for SI messagesmay be accomplished by sending a Random Access Preamble, which maycomprise a sequence selected from a set of available sequencesconfigured by the access node via Minimum SI. A given sequence isidentified by a Preamble Index. When the access node detects thetransmission of a preamble sequence, it may respond to it with RandomAccess Response, which includes the Preamble Index corresponding to thesequence. Upon receiving, the wireless terminal may validate that thePreamble index in the Random Access Response matches the one associatedwith the preamble sequence, and then send to the access nodeSystemInformationRequest message that includes the identity of the SImessages (e.g. SI # k) that the wireless terminal desires to receive. Inresponse, the access node may send a SystemInformation messageacknowledging the request, indicating that the requested SI message(s)will be broadcasted from the next SI window scheduled for the requestedSI message(s).

In one configuration, the access node may include in Minimum SI a set ofPreamble indices, each of which is designated for requesting on-demanddelivery of one or more specific SI messages. FIG. 9B illustrates anexample SI request procedure using this configuration, where thewireless terminal in any RRC state may transmit Random Access Preamblesequence given by the Preamble Index associated with the SI message(s)that the wireless terminal has selected. When the wireless terminalreceives Random Access Response including the Preamble Index, it mayconsider that the request procedure is successful.

The SI request procedure in FIG. 9C may be applicable to wirelessterminals in RRC_CONNECTED, wherein the SystemInformationRequest messageis sent without the random access preamble/response.

In any of the three options disclosed above, the wireless terminal mayproceed to the SI reception procedure if the SI request procedure issuccessful. Otherwise, the wireless terminal may think that the servingcell (controlled by the access node) is barred, which will invoke a cellreselection.

The SystemInformationRequest message shown in FIG. 9A or FIG. 9C mayinclude an information element (e.g. siRequest) to indicate which SImessage(s) that the wireless terminal desires to receive. In oneconfiguration, as shown in FIG. 10, the siRequest may comprise a bitmap, wherein each bit corresponds to a schedulingInfo informationelement in SIB1 of the current serving cell, the bits arranged in theorder of schedulingInfo information elements. By doing so, each bit ofthe bit map may correspond to a specific SI message. Alternatively,siRequest may carry a field indicating that the wireless terminaldesires to receive at least one on-demand basis SI message. In thiscase, the access node may start broadcasting all of the on-demand basisSI messages for a pre-configured duration. The SystemInformation messageshown in FIG. 9A or FIG. 9C may include siAck, an information elementfor acknowledging siRequest. In one configuration, siAck may comprisesthe same bit map as the one in SystemInformationRequest, indicating theSI message(s) to be broadcasted. Alternatively, siAck may comprise oneBoolean field, indicating whether the request has been accepted or not.

FIG. 11 is an exemplary message flow diagram of SI acquisition procedurefor a SI message broadcasted periodically. Act 11-0 comprises thewireless terminal 26, in either RRC_IDLE, RRC_INACTIVE or RRC_CONNECTEDstate, storing the content of SIB # A with the validity information,e.g., valueTag=a and si-AreaID=2. Act 11-1 comprises the wirelessterminal 26 obtaining, from the currently serving access node 22, SIB1as Minimum SI, which, as understood from previous description, includesone or more schedulingInfo information elements. In the scenario of FIG.11, and as shown by Table 2, the k'th schedulingInfo information elementindicates that the SI message associated with this schedulingInfo (SI #k, hereafter), containing SIB # A, is currently broadcastedperiodically. Furthermore, the SIB1 specifies (see Table 2) thatotherSIBInfo corresponding to SIB # A indicates that the validityinformation of SIB # A is now valueTag=b and si-AreaID=3.

Knowing that the stored SIB # A is now invalid, as act 11-3 the wirelessterminal 26 begins an SI reception procedure wherein the wirelessterminal may attempt to acquire the SI message (SI # k) in the SIwindows specified in SIB1. In FIG. 11, act 11-3 a illustrates anunsuccessful SI message reception attempt in a first SI window for SI #k, followed by act 11-3 b which is a successful SI message reception ina second SI window for SI # k, Thus, as shown in FIG. 11, if the SImessage is not received by the end of the SI window (as was the case foract 11-3 a), the wireless terminal 26 may repeat reception at the nextSI window occasion for the concerned SI message until it successfullyreceives the SI message (as was done in act 11-3 b).

TABLE 2 ... schedulingInfoList {   ...   k'th schdulingInfo (SI#k) {    ...     deliveryMethod = broadcast     SIB-type = A     ...   }  ...   } } ... otherSIBInfoList {   ...   otherISBInfo {     SIB-type =A     ValidityInfo {       valueTag = b       ...     }     ...   }  ... } ... si-AreaID = 3 ...

Unsuccessful Attempted Reception of On-Demand System Information

FIG. 12 shows an example communications system 20(12) comprisingwireless terminal 26(12) configured to detect failure of a SI receptionprocess involving an on-demand SI message, following a successfulcompletion of an SI request. The access node 22(12) and wirelessterminal 26(12) of FIG. 12 are essentially identical to the respectiveaccess node 22 and wireless terminal 26 of FIG. 2, except as otherwiseindicated herein. In terms of likeness, for example, the radio accessnode 22(12) comprises node processor 30 and node transceiver circuitry32, with the node processor 30 comprising, e.g., node frame/signalscheduler/handler 50, system information (SI) generator 54, and node RRCcontroller 60. Similarly, the wireless terminal 26(12) comprisesterminal processor 40, terminal transceiver circuitry 42, with terminalprocessor 40 comprising terminal frame/signal scheduler/handler 52,system information (SI) processor 56, and terminal RRC controller 70.

FIG. 12 also shows that wireless terminal 26(12) comprises systeminformation acquisition failure detector 80. The terminal processor 40,and particularly SI processor 56, may comprise or constitute the systeminformation acquisition failure detector 80. The system informationacquisition failure detector 80 is configured to make a determination ofa failure of the SI message acquisition process. The system informationacquisition failure detector 80 may make such failure determinationbased on a termination condition, as herein explained.

The system information generator 54 of radio access node 22(12) isconfigured to generate first type system information. For the exampleembodiment and mode of FIG. 12, and in an example, non-limiting mannershown in FIG. 13, the first type system information comprises(information elements or the like which indicate): availability ofsecond type SI messages; scheduling information of each of the SImessages; a delivery mode for each of the second type SI messages; and,a configuration parameter to configure at least one terminationcondition for determination of a failure of an SI message acquisitionprocess for the on-demand based second type SI messages.

As understood herein, a second type SI message comprises at least onesystem information block (SIB), and the delivery mode may be eitherperiodic broadcast or on-demand basis. The transmitter circuitry 36 ofradio access node 22(12) is configured to transmit the first type systeminformation over the radio interface 24 to the wireless terminal 26(12),as shown by arrow 12-1 in FIG. 12

As in the example embodiment and mode of FIG. 2, the on-demand Other SIrequest generator 72 of wireless terminal 26(12) may request at leastone second type SI using a request message as indicated by arrow 12-2 inFIG. 12. The second type SI request message depicted by arrow 12-2 isreceived by node receiver circuitry 36. The node processor 30, andparticularly the SI generator 54, generates the requested (second type)SI message in one or more windows of transmission, the transmission ofthe requested SI message being depicted by arrow 12-3 in FIG. 12.

As mentioned above, system information acquisition failure detector 80may make a determination of a failure of the SI message acquisitionprocess. When so doing, in an example embodiment and mode, the terminalprocessor 40, working in response to or with system informationacquisition failure detector 80, is configured to initiate acquisitionof the first type system information. That is, the terminal processor 40is configured, upon a failure of the SI message acquisition process, toinitiate acquisition of the first type system information, e.g., toagain request the first type system information (Minimum SI) from theradio access node 22(12). In FIG. 12 such request for first type systeminformation is depicted by arrow 12-4.

FIG. 13A is an exemplary format of SIB1, which is based on the formatshown in FIG. 7 with an additional information elementsi-MaxAcqAttempts. The information element si-MaxAcqAttempts provides atermination condition for the SI reception procedure, indicating themaximum number of SI message reception opportunities (e.g. SI windows)allowed before the end of the SI reception procedure. FIG. 13B is analternative format of SIB1, wherein the information elementue-TimersAndConstants includes a timer configuration (T # x) to be usedas a termination condition for the SI reception procedure.

FIG. 14 is an exemplary message flow diagram of on-demand based SIacquisition procedure wherein system information acquisition failure isdetected. As shown by act 14-0, wireless terminal 26, in eitherRRC_IDLE, RRC_INACTIVE or RRC_CONNECTED state stores the content of SIB# A with the validity information, valueTag=a, si-AreaID=2, which thewireless terminal has previously received. From the currently servingaccess node, as act 14-1 the wireless terminal may obtain SIB1 asMinimum SI, e.g., first type system information. Obtaining of the SIBIis depicted by arrow 12-1 in FIG. 12. As shown in FIG. 13, the SIB1includes the scheduleInfoList, which in turn may include one or moreschedulingInfo information elements. An example scheduleInfoList forthis scenario is shown in previously-discussed Table 1, wherein the k'thschedulingInfo indicates that the SI message associated with thisschedulingInfo (SI # k, hereafter), containing SIB # A, will beavailable by on-demand delivery. Furthermore, the otherSIBInfocorresponding to SIB # A indicates that the validity information of SIB# A is valueTag=b, si-AreaID=3. It is assumed hereafter that wheneverthe wireless terminal receives SIB1, it has already received MIBbeforehand.

Knowing that the stored SIB # A is now invalid, the wireless terminalmay decide to obtain a valid version of SIB # A, and may initiate the SIrequest procedure represented by act 14-2 and explained herein andillustrated by arrow 12-2 in FIG. 12. After the SI request procedure hasa successful result, the wireless terminal may start the SI receptionprocedure, shown generally as act 14-3 in FIG. 14. In the SI receptionprocedure the wireless terminal monitors signals from the access node(depicted by arrow 12-3 in FIG. 12) in the designated SI windows derivedfrom the scheduling information (scheduleInfo) in the SIB1, and therebyattempts to receive the requested SI # k. The SI windows are shown bydotted rectangles in FIG. 14. FIG. 14 shows by act 14-3 a, act 14-3 b,and act 14-3 c three successive transmissions of the requested SI # k,all of which are unsuccessful. A tail of a vertical down-pointing arrowin the SI reception procedure depiction of FIG. 14 is associated withstart of the SI reception procedure, while the head of the same verticaldown-pointing arrow is associated with end of the SI receptionprocedure. In FIG. 14, the SI reception procedure fails. Failure of theSI reception procedure is determined by system information acquisitionfailure detector 80 which, as indicated above, makes a determination ofa failure of the SI message acquisition process based on a terminationcondition. Examples of the termination condition are described below.

Upon detection of failure of the SI message acquisition process, as act14-4 the terminal processor 40 initiates (re)acquisition of the firsttype system information, e.g., the MINIMAL SI or SIB1, as shown by arrow12-4 in FIG. 12. The wireless terminal 26(12) thus attempts to againacquire the first type system information, in hopes that the SI messageacquisition process can thereafter be repeated and perhaps in suchrepeat of the SI message acquisition process the requested SI messagewill be obtained. In an example implementation, the wireless terminal26(12) may optionally reacquire MIB prior to reacquisition of SIB1.Accordingly, not having a valid version of a stored SIB, upon detectionof failure of the SI message acquisition process, the terminal processor40 initiates (re)acquisition of the first type system information.

FIG. 15 shows basic, representative, example acts or steps performed bythe wireless terminal 26(12) of FIG. 12. Act 15-1 comprises receivingthe first type system information (SI) from the base station apparatus.As mentioned above, the first type system information comprises:availability of a second type SI message, the second type SI messagecomprising at least one system information block (SIB); schedulinginformation for the SI message; an indication of a delivery mode for thesecond type SI message, the delivery mode being either periodicbroadcast or on-demand basis; and, at least one termination conditionfor determination of a failure of an SI message acquisition process forthe on-demand based second type SI message. Act 15-2 comprisestransmitting an SI request message to request at least one second typeSI message indicated as on-demand delivery. Act 15-3 comprisesinitiating the SI message acquisition process. Act 15-4 comprisesdetermining a failure of the SI message acquisition process. Act 15-5comprises, upon a failure of the SI message acquisition process,initiating acquisition of the first type system information.

FIG. 16 is a flowchart showing basic, representative, example acts orsteps performed by the access node 22(12) of FIG. 12. Act 16-1 comprisestransmitting first type system information (SI). The first type SI hasbeen described above. Act 16-2 comprises receiving an SI request messageto request at least one second type SI message. Act 16-3 comprisesdelivering the requested SI message. As understood from above, therequested SI message may be sent periodically, repeatedly transmitted ata predetermined interval, for a predetermined length of time.

It was mentioned above that, in one configuration, the wireless terminalmay use a counter, which is incremented at every SI window of aparticular SI message, e.g. SI # k, and that the SI reception proceduremay end when the requested SI message(s) are successfully received, orwhen the counter reaches a maximum counter value. In someconfigurations, the maximum counter value may be configured by SIB1(e.g. si-MaxAcqAttempts shown in FIG. 13A). FIG. 17A shows the systeminformation acquisition failure detector 80 as comprising such counteras SI window counter 82. Thus in one example implementation of the FIG.12 example embodiment and mode, the termination condition may compriseSI window counter 82 counting up to reach a maximum value, or countingdown from a pre-set value to zero. Such maximum or pre-set value may beconfigured by the radio access node 22(12). The SI window counter 82 isincremented (or decremented) in a case in which the requested SI messagewas not received by the end of one reception opportunity, e.g., a casein which the requested SI message was not received by the end of an SIwindow.

It was further mentioned above that, in another configuration thewireless terminal may start a timer at the beginning of the SI receptionprocedure, and that the SI reception procedure may end when therequested SI message(s) are successfully received, or when the timerexpires. In some configuration, the timer is configured by SIB1 (e.g.the timer configuration T # x in FIG. 13B). FIG. 17B shows the systeminformation acquisition failure detector 80 as comprising such a timer:SI message acquisition process timer 84. Thus in another exampleimplementation of the FIG. 12 example embodiment and mode, thetermination condition may comprise SI message acquisition process timer84 expiration of a timer configured by the base station apparatus. TheSI message acquisition process timer 84 is started at the beginning ofthe SI message acquisition process. The timer expiration value may beconfigured by the radio access node 22(12).

As understood from above, the Other SI may comprise one or more (Other)SI messages, also known as second type SI messages. In one exampleimplementation, as reflected by FIG. 18A, the termination condition maybe common for plural, e.g., all, SI messages. That is, in the FIG. 18Aimplementation, the maximum counter value in the case of FIG. 17A, orthe timer value in the case of FIG. 17B, may be common for all SImessages. In this case, the counter value configuration or the timerconfiguration in Minimum SI (e.g. si-MaxAcqAttempts in FIG. 13A, or T #x in FIG. 13B) may comprise a single parameter. Alternatively, as shownin the example implementation of FIG. 18B, the termination condition maybe configured on a per-SI message basis, e.g., uniquely configured forone or more (Other SI) SI messages. In this case, the counter valueconfiguration or the timer configuration in Minimum SI (e.g.si-MaxAcqAttempts in FIG. 13A, or T # x in FIG. 13B) may comprise a listof parameters, each of which configures a corresponding SI message. Ineither the FIG. 18A or FIG. 18B implementations, the terminationcondition(s), whether common or not common, e.g., unique, may bepre-configured or configured by network via system information. Thus,the condition for the wireless terminal to end the SI reception processis referred as a “termination condition” herein.

The foregoing is now discussed in context of a more general 3GPP TS SIacquisition procedure for a UE to acquire the AS- and NAS information.This more 3GPP TS procedure applies to UEs in RRC_IDLE, in RRC_INACTIVEand in RRC_CONNECTED. The UE in RRC_IDLE and RRC_INACTIVE shall ensurehaving a valid version of (at least) the MIB, SIB1 as well as SIB Xthrough SIB Y (depending on support of the concerned RATs for UEcontrolled mobility). The UE in RRC_CONNECTED shall ensure having avalid version of (at least) the MIB, SIB1 as well as SIB X (depending onsupport of mobility towards the concerned RATs).

For the acquisition of MIB and SIB1, the UE shall perform the acts below(wherein reference to any “section”, “clause”, or “sub-clause” is to therespective section, clause, or sub-clause of 3GPP TS 38.331.)

1> if the cell is a PSCell: 2> acquire the MIB; 2> perform the actionsspecified in section 5.2.2.4.1; 1> else: 2> acquire the MIB; 2> if theUE is unable to acquire the MIB; 3> perform the actions as specified inclause 5.2.2.5; 2> else: 3>  perform the actions specified in section5.2.2.4.1. 2> acquire the SIB1, 2> if the UE is unable to acquire theSIB1: 3> perform the actions as specified in clause 5.2.2.5; 2> else:3>perform the actions specified in section 5.2.2.4.2.

From the foregoing it is understood that the UE shall apply the SIacquisition procedure as defined above upon cell selection (e.g. uponpower on), cell-reselection, return from out of coverage, afterreconfiguration with sync completion, after entering NR-RAN from anotherRAT, upon receiving an indication that the system information haschanged, upon receiving a PWS notification, upon failing to acquire anSI message; whenever the UE does not have a valid version in the storedSI.

From the foregoing it is understood that, in an example implementation,when acquiring an SI message, the UE may perform the following acts:

-   -   1> determine the start of the SI-window for the concerned SI        message.    -   1> if SI message acquisition is not triggered due to UE request:        -   2> receive DL-SCH using the SI-RNTI from the start of the            SI-window and continue until the end of the SI-window whose            absolute length in time is given by si-WindowLength, or            until the SI message was received;        -   2> if the SI message was not received by the end of the            SI-window, repeat reception at the next SI-window occasion            for the concerned SI message;    -   1> else if SI message acquisition is triggered due to UE        request:        -   2> Set the SI window counter 82 to 0 (or Start SI message            acquisition process timer 84);        -   2>[FFS receive DL-SCH using the SI-RNTI from the start of            the SI-window and continue until the end of the SI-window            whose absolute length in time is given by si-WindowLength,            or until the SI message was received];        -   2>[FFS if the SI message was not received by the end of the            SI-window, increment the SI window counter 82, repeat            reception at the next SI-window occasion for the concerned            SI message];        -   2> if the SI window counter 82 is equal to configured            maximum value or counted down to zero (or timer SI message            acquisition process timer 84 expires)            -   3> Initiate the SI acquisition procedure.

When the UE acquires a MIB or a SIB1 or a SI message in a currentlycamped/serving cell as described in clause 5.2.2.3, the UE shall storethe acquired SI. A version of the SI that the UE stored is out of dateafter 3 hours. The UE may use such a stored version of the SI e.g. aftercell re-selection, upon return from out of coverage or after thereception of SI change indication. The storage and management of thestored SI in addition to the SI relevant for the current camped/servingcell is left to UE implementation. The UE shall:

-   -   1> delete any stored version of a SIB after 3 hours from the        moment it was successfully confirmed as valid;    -   1> if UE has stored version of any SIB:        -   2> for each SIB:            -   3> if the stored SIB is area specific SIB and if                systemInfoAreaIdentifier and systemInfoValueTag included                in the SIB1 received from the currently camped/serving                cell are identical to the systemInfoAreaIdentifier and                systemInfoValueTag associated with stored version of                that SIB; or            -   3> if the stored SIB is cell specific and if                systemInfoValueTag included in the SIB1 received from                the currently camped/serving cell is identical to the                systemInfoValueTag associated with stored version of                that SIB;                -   4> consider the stored SIB as valid for the cell;            -   3> else:                -   4> (re)acquire the corresponding SI message as                    specified in clause 5.2.2.3.    -   1> if UE has no stored version of a SIB:        -   2> (re)acquire the corresponding SI message as specified in            clause 5.2.2.3.

Unsuccessful Attempted Reception of Broadcasted System Information

The previous embodiments disclose, e.g., procedure(s) for acquiring anSI message currently broadcasted periodically, wherein the wirelessterminal may continue the SI reception procedure until successfulcompletion. This operation may be valid if the concerned SI message isassumed to be broadcasted forever. By the introduction of on-demand SI,however, the assumption is not guaranteed to be true. For instance, whenthe wireless terminal sees deliveryMode=broadcast in SIB1 for the SImessage of concern, it is possible that the access node may betemporarily broadcasting the SI message in response to a request fromanother wireless terminal, and that the access node may stop theperiodic broadcast eventually.

Whereas the example communications system 20(12) of FIG. 12 primarilyconcerns unsuccessful attempted reception of on-demand systeminformation, FIG. 19 shows an example communications system 20(17)comprising wireless terminal 26(17) configured to detect failure of a SIreception process involving a periodically broadcast SI message. Theaccess node 22(17) and wireless terminal 26(17) of FIG. 19 areessentially identical to the respective access node 22 and wirelessterminal 26 of FIG. 2 and FIG. 12, except as otherwise indicated herein.In terms of likeness, for example, the radio access node 22(17)comprises node processor 30 and node transceiver circuitry 32, with thenode processor 30 comprising, e.g., node frame/signal scheduler/handler50, system information (SI) generator 54, and node RRC controller 60.Similarly, the wireless terminal 26(17) comprises terminal processor 40,terminal transceiver circuitry 42, with terminal processor 40 comprisingterminal frame/signal scheduler/handler 52, system information (SI)processor 56, and terminal RRC controller 70.

FIG. 19 shows that wireless terminal 26(17) also comprises systeminformation acquisition failure detector 80. As in the case of FIG. 12,terminal processor 40, and particularly SI processor 56, may comprise orconstitute the system information acquisition failure detector 80. Thesystem information acquisition failure detector 80 is configured to makea determination of a failure of the SI message acquisition process. Thesystem information acquisition failure detector 80 may make such failuredetermination based on a termination condition, as herein explained.

As in the FIG. 12 example embodiment and mode, system informationgenerator 54 of radio access node 22(12) is configured to generate firsttype system information. For the example embodiment and mode of FIG. 19,and in the example, non-limiting manner shown in FIG. 13, the first typesystem information comprises (information elements or the like whichindicate): availability of second type SI messages; schedulinginformation of each of the SI messages; a delivery mode for each of thesecond type SI messages; and, a configuration parameter to configure atleast one termination condition for determination of a failure of an SImessage acquisition process for the on-demand based second type SImessages. As understood herein, a second type SI message comprises atleast one system information block (SIB), and the delivery mode may beeither periodic broadcast or on-demand basis. The transmitter circuitry36 of radio access node 22(17) is configured to transmit the first typesystem information over the radio interface 24 to the wireless terminal26(17), as shown by arrow 19-1 in FIG. 19.

In the FIG. 19 example embodiment and mode it is assumed that wirelessterminal 26(17) is presently concerned with acquiring a second type SImessage for which the delivery mode is periodic broadcast. As such, theterminal processor 40 is controlling terminal receiver 46 to initiate aSI message acquisition process for a periodically broadcasted secondtype SI message. But it may turn out, however, after initiating the SImessage acquisition process, that the expected periodically broadcastedsecond type SI message(s) are not received. Non-receipt of theperiodically broadcasted second type SI message(s) may be for any ofseveral reasons, including the fact that the broadcast of theperiodically broadcasted second type SI message was at the behest ofanother wireless terminal, with the wireless terminal 26(17) essentiallybeing a third-party beneficiary of the broadcasts, and the access nodehas by now terminated the broadcast of the second type SI messageintended for the another wireless terminal.

Thus, as in the FIG. 12 example embodiment and mode, system informationacquisition failure detector 80 may make a determination of a failure ofthe SI message acquisition process. When so doing, in an exampleembodiment and mode, the terminal processor 40, working in response toor with system information acquisition failure detector 80, isconfigured to initiate acquisition of the first type system information.That is, the terminal processor 40 is configured, upon a failure of theSI message acquisition process involving a periodically broadcastedsecond type SI message, to initiate acquisition of the first type systeminformation, e.g., to again request the first type system information(Minimum SI) from the radio access node 22(17). In FIG. 19 such requestfor first type system information is depicted by arrow 19-4 (there beingno arrow 19-2 or arrow 19-3 in FIG. 19).

FIG. 20 is an exemplary message flow diagram of a periodic broadcastbased SI acquisition procedure wherein system information acquisitionfailure is detected. As shown by act 20-0, wireless terminal 26, ineither RRC_IDLE, RRC_INACTIVE or RRC_CONNECTED state stores the contentof SIB # A with the validity information, valueTag=a, si-AreaID=2, whichthe wireless terminal has previously received. From the currentlyserving access node, as act 20-1 the wireless terminal may obtain SIB1as Minimum SI, e.g., first type system information. Obtaining of theSIB1 is also depicted by arrow 19-1 in FIG. 19. As shown in FIG. 13, theSIB1 includes the scheduleInfoList, which in turn may include one ormore schedulingInfo information elements. An example scheduleInfoListfor this scenario is shown in previously-discussed Table 3, wherein thek'th schedulingInfo indicates that the SI message associated with thisschedulingInfo (SI # k, hereafter), containing SIB # A, will beavailable by broadcast. Furthermore, the otherSIBInfo corresponding toSIB # A indicates that the validity information of SIB # A isvalueTag=b, si-AreaID=3. It is assumed hereafter that whenever thewireless terminal receives SIB1, it has already received MIB beforehand.

Having received the SIB1 as Minimum SI, e.g., first type systeminformation, the wireless terminal 26(17) knows when the radio accessnode 22(17) is expected to broadcast the system information for thesought second type SI, e.g., SIB # A. As such, the terminal processor 40of wireless terminal 26(17) begins the SI reception procedure(represented by act 20-3 in FIG. 20).

In the SI reception procedure 20-3, the wireless terminal monitorssignals from the access node attempts to obtain the SI messages in thedesignated SI windows derived from the scheduling information(scheduleInfo) in the SIB1, and thereby attempts to receive therequested SI # k. The SI windows are shown by dotted rectangles in FIG.20. FIG. 20 shows by act 20-3 a, act 20-3 b, and act 20-3 c threesuccessive transmissions of the requested SI # k, all of which areunsuccessful. A tail of a vertical down-pointing arrow in the SIreception procedure depiction of FIG. 20 is associated with start of theSI reception procedure, while the head of the same verticaldown-pointing arrow is associated with end of the SI receptionprocedure. In FIG. 20, the SI reception procedure 20-3 utterly fails.Failure of the SI reception procedure is determined by systeminformation acquisition failure detector 80 which, as indicated above,makes a determination of a failure of the SI message acquisition processbased on a termination condition. Examples of the termination conditionare described herein.

Upon detection of failure of the SI message acquisition process, as act20-4 the terminal processor 40 initiates (re)acquisition of the firsttype system information, e.g., the MINIMAL SI or SIB1, as shown by arrow20-4 in FIG. 20. The wireless terminal 26(14) thus attempts to againacquire the first type system information, in hopes that the SI messageacquisition process can thereafter be repeated and perhaps in suchrepeat of the SI message acquisition process the requested SI messagewill be obtained. In an example implementation, the wireless terminal26(14) may optionally reacquire MIB prior to reacquisition of SIB1.Accordingly, not having a valid version of a stored SIB, upon detectionof failure of the SI message acquisition process, the terminal processor40 initiates (re)acquisition of the first type system information.

FIG. 21 is a flowchart showing basic, representative, example acts orsteps performed by the wireless terminal of FIG. 19. Act 21-1 comprisesreceiving first type system information (SI) from the base stationapparatus. As indicated previously, the first type system informationcomprises: availability of a second type SI message; schedulinginformation for the SI message; an indication of a delivery mode for thesecond type SI message, the delivery mode being either periodicbroadcast or on-demand basis; and, at least one termination conditionfor determination of a failure of an SI message acquisition process. Act21-2 comprises initiating the SI message acquisition process for aperiodically broadcasted second type SI message. Act 21-3 comprisesdetermining a failure of the SI message acquisition process. Act 21-4comprises, upon a failure of the SI message acquisition process,initiating acquisition of the first type system information.

FIG. 22 is a flowchart showing basic, representative, example acts orsteps performed by the access node of FIG. 19. Act 22-1 comprisestransmitting first type system information (SI) from the base stationapparatus. The first type system information comprises, e.g.,configuration parameters to configure for at least one terminationcondition for determination of a failure of an SI message acquisitionprocess. Act 22-2 comprises broadcasting the periodic broadcast-based SImessages.

As in the FIG. 12 embodiment and mode, wireless terminal 26(17) may usea counter, which is incremented at every SI window of a particular SImessage, e.g. SI # k, and may end the SI reception procedure when therequested SI message(s) are successfully received, or when the counterreaches a maximum counter value. The system information acquisitionfailure detector 80 of FIG. 19 may comprise the aforementioned SI windowcounter 82, shown in FIG. 17A, which may count up to reach a maximumvalue, or count down from a pre-set value to zero. Such maximum orpre-set value may be configured by the radio access node 22(17). The SIwindow counter 82 is incremented (or decremented) in a case in which therequested SI message was not received by the end of one receptionopportunity, e.g., a case in which the requested SI message was notreceived by the end of an SI window.

Also as in the FIG. 12 embodiment and mode, wireless terminal 26(17) maystart a timer at the beginning of the SI reception procedure, and mayend the SI reception procedure when the requested SI message(s) aresuccessfully received, or when the timer expires. The system informationacquisition failure detector 80 of FIG. 19 may comprise theaforementioned SI message acquisition process timer 84 shown in FIG. 17Bwhen the termination condition comprises expiration of acquisitionprocess timer 84. The SI message acquisition process timer 84 is startedat the beginning of the SI message acquisition process. The timerexpiration value may be configured by the radio access node 22(17).

Thus, similar to the example embodiments and modes of FIG. 2 and FIG.12, for acquisition of periodic broadcast-based SI message(s) as shownin FIG. 19 an extra mechanism to terminate the SI reception proceduremay employed. In one configuration, the wireless terminal may use acounter, which is incremented at every SI window of a particular SImessage (e.g. SI # k). In this configuration, the SI reception proceduretriggered by acquiring may end when the requested SI message issuccessfully received, or when the counter reaches a maximum countervalue. (It should be understood that this counter implementation islogically identical to an alternative implementation, wherein thecounter is set with the maximum counter value at the beginning of the SIreception procedure and decremented upon the end of the SI window. Inthis implementation, the SI reception procedure may end when the counterbecomes a pre-determined value, such as zero). In another configurationthe wireless terminal starts a timer at the beginning of the SIreception procedure. In this configuration, the SI reception proceduremay end when the requested SI message is successfully received, or whenthe timer expires. Similar to the embodiment of FIG. 12, and asunderstood by FIG. 18A and FIG. 18B, the maximum counter value, or thetimer value, may be common for all SIB types, per-SIB type basis orper-SI message basis, may be pre-configured or configured by network viasystem information.

It should further be understood that a wireless terminal may beattempting to receive some second type SI by periodic broadcast, and oneor more other second type SI by on-demand delivery. Hence, in a furtherexample embodiment and mode the terminal processor 40 of a wirelessterminal, such as wireless terminal 26(17), may be configured to bothdetect failure of a SI message acquisition process for broadcastedsecond type system information and detect failure of a SI messageacquisition process for on-demand second type system information. Forthis reason the terminal processor 40 of wireless terminal 26(17) showsterminal processor 40 and SI processor 56 in particular as stillcomprising on-demand Other SI request generator 72. Thus it is possiblein some modes for both the process of FIG. 14 and FIG. 19 to beexecuting essentially currently.

When a wireless terminal 26 is capable of both detecting failure of a SImessage acquisition process for broadcasted second type systeminformation and detecting failure of a SI message acquisition processfor on-demand second type system information, the wireless terminal 26may have separate termination conditions for each process. For thatreason the wireless terminal 26 may comprise plural SI window counters82 and/or plural SI message acquisition process timers 84. For example,the wireless terminal may have a first SI window counter 82(B) for a SImessage acquisition process for broadcasted second type systeminformation; and a second SI window counter 82(D) for a SI messageacquisition process for on-demand second type system information. Or,for example, wireless terminal may have a first SI message acquisitionprocess timer 84(B) for a SI message acquisition process for broadcastedsecond type system information; and a second SI message acquisitionprocess timer 84(D) for a SI message acquisition process for on-demandsecond type system information.

Furthermore, the counter configuration or the timer configuration foracquisition of periodic broadcast-based SI message(s) may be configuredvia system information (e.g. SIB1) separately from the configuration foracquisition of on-demand based SI message(s). In this case, SIB1 shownin FIG. 13C with two separate counter configurations(si-MaxAcqAttemptsOnDemand and si-MaxAcqAttemptsPeriodic) or FIG. 13Dwith two separate timer configurations (T # x for on-demand and T # yfor periodic broadcast) may be used. Alternatively, the counter/timerconfiguration common for on-demand and periodic broadcast-based SImessage acquisition may be configured. In this case, SIB1 shown in FIG.13A (common counter configuration) or FIG. 13B (common timerconfiguration) may be used.

The aforementioned more general 3GPP TS SI acquisition procedure for aUE to acquire the AS- and NAS information may be modified in part, e.g.,for acquisition of an SI Message, for the example embodiment and mode ofFIG. 19 as shown below. As indicated earlier, the counters (SI windowcounter 82(B) and SI window counter 82(D)) or the timers (SI messageacquisition process timer 84(B) and SI message acquisition process timer84(D)) may be identical, or alternatively separately configured.

When acquiring an SI message, the UE shall:

-   -   1> determine the start of the SI-window for the concerned SI        message as follows:    -   1> if SI message acquisition is not triggered due to UE request:        -   2> Set the counter SI window counter 82(B) to 0 (or Start            timer SI message acquisition process timer 84(B));        -   2> receive DL-SCH using the SI-RNTI from the start of the            SI-window and continue until the end of the SI-window whose            absolute length in time is given by si-WindowLength, or            until the SI message was received;        -   2> if the SI message was not received by the end of the            SI-window, increment the counter SI window counter 82(B),            repeat reception at the next SI-window occasion for the            concerned SI message;        -   2> if the counter SI window counter 82(B) is equal to            [configured maximum value] (or timer SI message acquisition            process timer 84(B) expires)            -   3> Initiate the SI acquisition procedure as defined in                sub-clause 5.2.2.3.    -   1> else if SI message acquisition is triggered due to UE        request:        -   2> Set the counter SI window counter 82(D) to 0 (or Start            timer SI message acquisition process timer 84(D));        -   2>[receive DL-SCH using the SI-RNTI from the start of the            SI-window and continue until the end of the SI-window whose            absolute length in time is given by si-WindowLength, or            until the SI message was received];        -   2>[if the SI message was not received by the end of the            SI-window, increment the counter SI window counter 82(D),            repeat reception at the next SI-window occasion for the            concerned SI message];        -   2> if the counter SI window counter 82(D) is equal to            [configured maximum value] (or timer SI message acquisition            process timer 84(D) expires)            -   3> Initiate the SI acquisition procedure as defined in                sub-clause 5.2.2.3.

Features from each of the example embodiments and modes described hereinmay be combined with one another. For example information elementsdescribed in conjunction with the example embodiment and mode of FIG. 2may also be utilized with the other example embodiments and modesdescribed herein, including but not limited to the example embodimentand mode of FIG. 14 and FIG. 19. Further, features of the “ExampleEmbodiments” enumerated hereinafter may also be used in conjunction withone another.

Certain units and functionalities of node 22, node 22-12, node 22-17,wireless terminal 26, wireless terminal 26-14, and wireless terminal26-17 are, in example embodiments, implemented by electronic machinery,computer, and/or circuitry. For example, the node processors 30 andterminal processors 40 of the example embodiments herein describedand/or encompassed may be comprised by the computer circuitry of FIG.23. FIG. 23 shows an example of such electronic machinery or circuitry,whether node or terminal, as comprising one or more processor(s)circuits 190, program instruction memory 192; other memory 194 (e.g.,RAM, cache, etc.); input/output interfaces 196; peripheral interfaces198; support circuits 199; and busses 200 for communication between theaforementioned units.

The program instruction memory 192 may comprise coded instructionswhich, when executed by the processor(s), perform acts including but notlimited to those described herein. Thus is understood that each of nodeprocessor 30 and terminal processor 40, for example, comprise memory inwhich non-transient instructions are stored for execution.

The memory 194, or computer-readable medium, may be one or more ofreadily available memory such as random access memory (RAM), read onlymemory (ROM), floppy disk, hard disk, flash memory or any other form ofdigital storage, local or remote, and is preferably of non-volatilenature. The support circuits 199 are coupled to the processors 190 forsupporting the processor in a conventional manner. These circuitsinclude cache, power supplies, clock circuits, input/output circuitryand subsystems, and the like.

Further, it should be understood that, when a processor or processorcircuitry is mentioned in conjunction with any of the preceding exampleembodiments and modes, it should be understood that the device hostingthe processor, whether wireless terminal or access node, may comprise atleast one processor and at least one memory including computer programcode, the memory and the computer program code being configured to,working with the at least one processor, to cause the host device toperform the functions afore-described.

Thus, the technology disclosed herein solves problems in the field oftelecommunications, including problems in telecommunications nodes suchwireless terminals and access nodes, as well as computers/processors andhardware comprising such nodes. System information is of utmostimportance to the operation of telecommunication nodes, so that eachnode can obtain the necessary network information to coordinate andcommunicate with other nodes and to perform its desired functions. Thesystem information is quite extensive and complex, and may bechangeable/updateable due to network and operating conditions, forexample. Efficiently obtaining and using the system information ischallenging, particularly in view of numerous other telecommunicationsfunctions that may be simultaneously on-going based on the systeminformation. The technology disclosed herein solves problem that mayoccur when SI messages are not timely received by, e.g., curtailing SIreception procedures and initiating remedial measures such asre-acquiring SIB1. The technology disclosed herein thus avoids waste oftime and undue expenditure of processing resources.

The technology of this application thus encompasses but is not limitedto the following example embodiments, example features, and exampleadvantages, wherein the suffix “D” refers to an on-demand exampleembodiment and the suffix “B” refers to a periodic broadcast exampleembodiment:

Example Embodiment 1D

A user equipment that communicates over a radio interface with a basestation apparatus of a radio access network (RAN), the user equipmentcomprising:

receiver circuitry configured to receive first type system information(SI) from the base station apparatus, the first type SI comprising:

-   -   availability of a second type SI message, the second type SI        message comprising at least one system information block (SIB);    -   scheduling information for the SI message;    -   an indication of a delivery mode for the second type SI message,        the delivery mode being either periodic broadcast or on-demand        basis; and    -   at least one termination condition for determination of a        failure of an SI message acquisition process;

transmitter circuitry configured to transmit an SI request message torequest at least one second type SI message indicated as on-demanddelivery;

processor circuitry configured:

-   -   to use the receiver circuitry to initiate the SI message        acquisition process;    -   to make a determination of a failure of the SI message        acquisition process based on the termination condition; and    -   upon a failure of the SI message acquisition process, to        initiate acquisition of the first type system information.

Example Embodiment 2D

The user equipment of Example Embodiment 1D, wherein the terminationcondition comprises a counter reaching a maximum value configured by thebase station apparatus, the counter incremented in a case where therequested SI message was not received by the end of one receptionopportunity.

Example Embodiment 3D

The user equipment of Example Embodiment 2D, wherein the receptionopportunity is an SI window configured by the base station apparatus.

Example Embodiment 4D

The user equipment of Example Embodiment 1D, wherein the terminationcondition comprises a counter reaching zero from a preset valueconfigured by the base station apparatus, the counter decremented in acase where the requested SI message was not received by the end of onereception opportunity.

Example Embodiment 5D

The user equipment of Example Embodiment 4D, wherein the receptionopportunity is an SI window configured by the base station apparatus.

Example Embodiment 6D

The user equipment of Example Embodiment 1D, wherein the terminationcondition comprises an expiration of a timer configured by the basestation apparatus, the timer starting upon start of the SI messageacquisition process.

Example Embodiment 7D

A method for a user equipment that communicates over a radio interfacewith a base station apparatus of a radio access network (RAN),comprising:

receiving first type system information (SI) from the base stationapparatus, the first type SI comprising:

-   -   availability of a second type SI message, the second type SI        message comprising at least one system information block (SIB);    -   scheduling information for the SI message;    -   an indication of a delivery mode for the second type SI message,        the delivery mode being either periodic broadcast or on-demand        basis;    -   at least one termination condition for determination of a        failure of an SI message acquisition process for the on-demand        based second type SI message;

transmitting an SI request message to request at least one second typeSI message indicated as on-demand delivery;

initiating the SI message acquisition process;

determining a failure of the SI message acquisition process; and

upon a failure of the SI message acquisition process initiatingacquisition of the first type system information.

Example Embodiment 8D

The method of Example Embodiment 7D, wherein the failure of the SImessage acquisition process is determined by a counter reaching amaximum value configured by the base station apparatus, the counterincremented in a case where the requested SI message was not received bythe end of one reception opportunity.

Example Embodiment 9D

The method of Example Embodiment 7D, wherein the reception opportunityis an SI window configured by the base station apparatus.

Example Embodiment 10D

The method of Example Embodiment 7D, wherein the failure of theacquisition process is determined by an expiration of a timer configuredby the base station apparatus, the timer starting upon start of the SImessage acquisition process.

Example Embodiment 11D

A base station apparatus of a radio access network (RAN) thatcommunicates over a radio interface with a user equipment, the basestation apparatus comprising:

transmitter circuitry configured to transmit first type systeminformation (SI), the first type SI comprising:

-   -   availability of a second type SI message, the second type SI        message comprising at least one system information block (SIB);    -   scheduling information for the SI message;    -   an indication of a delivery mode for the second type SI message,        the delivery mode being either periodic broadcast or on-demand        basis;    -   a configuration parameter to configure at least one termination        condition for determination of a failure of an SI message        acquisition process for the on-demand second type SI message;

receiver circuitry configured to receive an SI request message torequest at least one second type SI message;

processor circuitry configured to use the transmitter circuitry todeliver the requested SI message.

Example Embodiment 12D

The base station apparatus of Example Embodiment 11D, wherein thetermination condition comprises a counter reaching a maximum valueconfigured by the base station apparatus, the counter incremented in thecase where the requested SI message was not received by the end of onereception opportunity.

Example Embodiment 13D

The base station apparatus of Example Embodiment 12D, wherein thereception opportunity is an SI window configured by the base stationapparatus.

Example Embodiment 14D

The base station apparatus of Example Embodiment 11D, wherein thetermination condition comprises an expiration of a timer configured bythe base station apparatus, the timer starting upon start of the SImessage acquisition process.

Example Embodiment 15D

A method for a base station apparatus of a radio access network (RAN)that communicates over a radio interface with a user equipment,comprising:

transmitting first type system information (SI), the first type SIcomprising:

-   -   availability of a second type SI message, the second type SI        message comprising at least one system information block (SIB);    -   scheduling information for the SI message;    -   an indication of a delivery mode for the second type SI message,        the delivery mode being either periodic broadcast or on-demand        basis;    -   a configuration parameter to configure at least one termination        condition for determination of a failure of an SI message        acquisition process for the on-demand second type SI message;

receiving an SI request message to request at least one second type SImessage;

delivering the requested SI message.

Example Embodiment 16D

The method of Example Embodiment 15D, wherein the termination conditioncomprises a counter reaching a maximum value configured by the basestation apparatus, the counter incremented in the case where therequested SI message was not received by the end of one receptionopportunity.

Example Embodiment 17D

The method of Example Embodiment 16D, wherein the reception opportunityis an SI window configured by the base station apparatus.

Example Embodiment 18D

The method of Example Embodiment 15D, wherein the termination conditioncomprises an expiration of a timer configured by the base stationapparatus, the timer starting upon start of the SI message acquisitionprocess.

Example Embodiment 19D

A user equipment that communicates over a radio interface with a basestation apparatus of a radio access network (RAN), the user equipmentcomprising:

processor circuitry configured to initiate a first type systeminformation block (SIB) acquisition process to receive a first type SIB,the first type SIB comprising:

-   -   scheduling information of a system information (SI) message, the        SI message comprising at least one second type SIB; and    -   an indication of broadcast status for the SI message, the        indication indicating on-demand delivery;

receiver circuitry configured to receive the first type SIB; and

transmitter circuitry configured to transmit an SI request message torequest the SI message;

the processor circuitry further configured to initiate an SI messageacquisition process to receive the SI message; wherein

in a case that a stored version of one of the at least one second typeSIB is not valid, the first type SIB acquisition process is initiatedupon a failure of the SI message acquisition process.

Example Embodiment 20D

The user equipment of Example Embodiment 19D, wherein the processorcircuitry is further configured to re-initiate the SI messageacquisition process based on the first type SIB acquisition processbeing initiated upon the failure of the SI message acquisition process.

Example Embodiment 21D

A method for a user equipment that communicates over a radio interfacewith a base station apparatus of a radio access network (RAN), themethod comprising:

initiating a first type system information block (SIB) acquisitionprocess to receive a first type SIB, the first type SIB comprising:

-   -   scheduling information of a system information (SI) message, the        SI message comprising at least one second type SIB; and    -   an indication of broadcast status for the SI message, the        indication indicating on-demand delivery;

receiving the first type SIB;

transmitting an SI request message to request the SI message; and

initiating an SI message acquisition process to receive the SI message;wherein

in a case that a stored version of one of the at least one second typeSIB is not valid, the first type SIB acquisition process is initiatedupon a failure of the SI message acquisition process.

Example Embodiment 22D

The method of Example Embodiment 21D, further comprising re-initiatingthe SI message acquisition process based on the first type SIBacquisition process being initiated upon the failure of the SI messageacquisition process.

Example Embodiment 23D

A base station apparatus of a radio access network (RAN) thatcommunicates over a radio interface with a user equipment, the basestation apparatus comprising:

transmitter circuitry configured to transmit first type systeminformation block (SIB), the first type SIB comprising:

-   -   scheduling information of a system information (SI) message, the        SI message comprising at least one second type SIB; and    -   an indication of broadcast status for the SI message, the        indication indicating on-demand delivery;

receiver circuitry configured to receive an SI request message torequest the SI message;

processor circuitry configured to use the transmitter circuitry todeliver the SI message; wherein

the first type SIB is re-acquired by the user equipment upon the userequipment failing on an SI message acquisition process to receive the SImessage, in a case that a version of one of the at least one second typeSIB stored in the user equipment is not valid.

Example Embodiment 24D

The base station apparatus of Example Embodiment 23D, wherein the firsttype SIB re-acquired by the user equipment is used by the user equipmentto re-initiate the SI message acquisition process.

Example Embodiment 25D

A method for a base station apparatus of a radio access network (RAN)that communicates over a radio interface with a user equipment,comprising:

transmitting first type system information block (SIB), the first typeSIB comprising:

-   -   scheduling information of a system information (SI) message, the        SI message comprising at least one second type SIB; and    -   an indication of broadcast status for the second type SI        message, the indication indicating on-demand delivery;

receiving an SI request message to request the SI message;

delivering the SI message; wherein

the first type SIB is re-acquired by the user equipment upon the userequipment failing on an SI message acquisition process to receive the SImessage, in a case that a version of one of the at least one second typeSIB stored in the user equipment is not valid.

Example Embodiment 26D

The method Example Embodiment 25D, wherein the first type SIBre-acquired by the user equipment is used by the user equipment tore-initiate the SI message acquisition process.

Example Embodiment 1B

A user equipment that communicates over a radio interface with a basestation apparatus of a radio access network (RAN), the user equipmentcomprising:

receiver circuitry configured to receive first type system information(SI) from the base station apparatus, the first type system informationcomprising:

-   -   availability of a second type SI message, the second type SI        message comprising at least one system information block (SIB);    -   scheduling information for the SI message;    -   an indication of a delivery mode for the second type SI message,        the delivery mode being either periodic broadcast or on-demand        basis; and    -   at least one termination condition for determination of a        failure of an SI message acquisition process;

processor circuitry configured:

-   -   to use the receiver circuitry to initiate the SI message        acquisition process for a periodically broadcasted second type        SI message;    -   to make a determination of a failure of the SI message        acquisition process based on the termination condition; and    -   upon a failure of the SI message acquisition process, to        initiate acquisition of the first type system information.

Example Embodiment 2B

The user equipment of Example Embodiment 1B, wherein the terminationcondition comprises a counter reaching a maximum value configured by thebase station apparatus, the counter incremented in the case where therequested SI message was not received by the end of one receptionopportunity.

Example Embodiment 3B

The user equipment of Example Embodiment 2B, wherein the receptionopportunity is an SI window configured by the base station apparatus.

Example Embodiment 4B

The user equipment of Example Embodiment 1B, wherein the terminationcondition comprises an expiration of a timer configured by the basestation apparatus, the timer starting upon start of the SI messageacquisition process.

Example Embodiment 5B

The user equipment of Example Embodiment 1B, wherein the terminationcondition is also used for an SI message acquisition process ofon-demand basis second type SI messages.

Example Embodiment 6B

The user equipment of Example Embodiment 1B, wherein the terminationcondition is dedicated for SI message acquisition process ofperiodically broadcasted basis second type SI messages.

Example Embodiment 7B

The user equipment of Example Embodiment 6B, wherein the first type SIfurther comprises at least one termination condition dedicated for theSI message acquisition process of on-demand basis second type SImessages.

Example Embodiment 8B

A method for a user equipment that communicates over a radio interfacewith a base station apparatus of a radio access network (RAN),comprising:

receiving first type system information (SI) from the base stationapparatus, the first type system information comprising:

-   -   availability of a second type SI message, the second type SI        message comprising at least one system information block (SIB);    -   scheduling information for the SI message;    -   an indication of a delivery mode for the second type SI message,        the delivery mode being either periodic broadcast or on-demand        basis;    -   at least one termination condition for determination of a        failure of an SI message acquisition process;

initiating the SI message acquisition process for a periodicallybroadcasted second type SI message;

determining a failure of the SI message acquisition process; and

upon a failure of the SI message acquisition process, initiatingacquisition of the first type system information.

Example Embodiment 9B

The method of Example Embodiment 8B, wherein the failure of the SImessage acquisition process is determined by a counter reaching amaximum value configured by the base station apparatus, the counterincremented in the case where the requested SI message was not receivedby the end of one reception opportunity.

Example Embodiment 10B

The method of Example Embodiment 9B, wherein the reception opportunityis an SI window configured by the base station apparatus.

Example Embodiment 11B

The method of Example Embodiment 8B, wherein the failure of theacquisition process is determined by an expiration of a timer configuredby the base station apparatus, the timer starting upon start of the SImessage acquisition process.

Example Embodiment 12B

The method of Example Embodiment 8B, wherein the termination conditionis dedicated for SI message acquisition process of periodicallybroadcasted basis second type SI messages.

Example Embodiment 13B

The method of Example Embodiment 12B, wherein the first type SI furthercomprises at least one termination condition dedicated for the SImessage acquisition process of on-demand basis second type SI messages.

Example Embodiment 14B

A base station apparatus of a radio access network (RAN) thatcommunicates over a radio interface with a user equipment, the basestation apparatus comprising:

transmitter circuitry configured to transmit first type systeminformation (SI), the first type SI comprising:

-   -   availability of a second type SI message, the second type SI        message comprising at least one system information block (SIB);    -   scheduling information for the SI message;    -   an indication of a delivery mode for the second type SI message,        the delivery mode being either periodic broadcast or on-demand        basis;    -   configuration parameters to configure for at least one        termination condition for determination of a failure of an SI        message acquisition process;

processor circuitry configured to use the transmitter circuitry tobroadcast the periodic broadcast-based SI messages.

Example Embodiment 15B

The base station apparatus of Example Embodiment 14B, wherein thetermination condition comprises a counter reaching a maximum valueconfigured by the base station apparatus, the counter incremented in thecase where the requested SI message was not received by the end of onereception opportunity.

Example Embodiment 16B

The base station apparatus of Example Embodiment 15B, wherein thereception opportunity is an SI window configured by the base stationapparatus.

Example Embodiment 17B

The base station apparatus of Example Embodiment 14B, wherein thetermination condition comprises an expiration of a timer configured bythe base station apparatus, the timer starting upon start of the SImessage acquisition process.

Example Embodiment 18B

The base station apparatus of Example Embodiment 14, wherein thetermination condition is also used for an SI message acquisition processof on-demand basis second type SI messages.

Example Embodiment 19B

The base station apparatus of Example Embodiment 14B, wherein thetermination condition is dedicated for SI message acquisition process ofperiodically broadcasted basis second type SI messages.

Example Embodiment 20B

The base station apparatus of Example Embodiment 19B, wherein the firsttype SI further comprises at least one termination condition dedicatedfor the SI message acquisition process of on-demand basis second type SImessages.

Example Embodiment 21B

A method for a base station apparatus of a radio access network (RAN)that communicates over a radio interface with a user equipment,comprising:

transmitting first type system information (SI) from the base stationapparatus, the first type system information comprising:

-   -   availability of a second type SI message, the second type SI        message comprising at least one system information block (SIB);    -   scheduling information for the SI message;    -   an indication of a delivery mode for the second type SI message,        the delivery mode being either periodic broadcast or on-demand        basis;    -   configuration parameters to configure for at least one        termination condition for determination of a failure of an SI        message acquisition process;

broadcasting the periodic broadcast-based SI messages.

Example Embodiment 22B

The method of Example Embodiment 21B, wherein the termination conditioncomprises a counter reaching a maximum value configured by the basestation apparatus, the counter incremented in the case where therequested SI message was not received by the end of one receptionopportunity.

Example Embodiment 23B

The method of Example Embodiment 22B, wherein the reception opportunityis an SI window configured by the base station apparatus.

Example Embodiment 24B

The method of Example Embodiment 21B, wherein the termination conditioncomprises an expiration of a timer configured by the base stationapparatus, the timer starting upon start of the SI message acquisitionprocess.

Example Embodiment 25B

The method of Example Embodiment 21B, wherein the termination conditioncomprises an expiration of a timer configured by the base stationapparatus, the timer starting upon start of the SI message acquisitionprocess.

Example Embodiment 26B

The method of Example Embodiment 21B, wherein the termination conditionis also used for an SI message acquisition process of on-demand basissecond type SI messages.

Example Embodiment 27B

The method of Example Embodiment 25B, wherein the termination conditionis dedicated for SI message acquisition process of periodicallybroadcasted basis second type SI messages.

Although the processes and methods of the disclosed embodiments may bediscussed as being implemented as a software routine, some of the methodsteps that are disclosed therein may be performed in hardware as well asby a processor running software. As such, the embodiments may beimplemented in software as executed upon a computer system, in hardwareas an application specific integrated circuit or other type of hardwareimplementation, or a combination of software and hardware. The softwareroutines of the disclosed embodiments are capable of being executed onany computer operating system, and is capable of being performed usingany CPU architecture. The instructions of such software are stored onnon-transient computer readable media.

The functions of the various elements including functional blocks,including but not limited to those labeled or described as “computer”,“processor” or “controller”, may be provided through the use of hardwaresuch as circuit hardware and/or hardware capable of executing softwarein the form of coded instructions stored on computer readable medium.Thus, such functions and illustrated functional blocks are to beunderstood as being either hardware-implemented and/orcomputer-implemented, and thus machine-implemented.

In terms of hardware implementation, the functional blocks may includeor encompass, without limitation, digital signal processor (DSP)hardware, reduced instruction set processor, hardware (e.g., digital oranalog) circuitry including but not limited to application specificintegrated circuit(s) [ASIC], and/or field programmable gate array(s)(FPGA(s)), and (where appropriate) state machines capable of performingsuch functions.

In terms of computer implementation, a computer is generally understoodto comprise one or more processors or one or more controllers, and theterms computer and processor and controller may be employedinterchangeably herein. When provided by a computer or processor orcontroller, the functions may be provided by a single dedicated computeror processor or controller, by a single shared computer or processor orcontroller, or by a plurality of individual computers or processors orcontrollers, some of which may be shared or distributed. Moreover, useof the term “processor” or “controller” shall also be construed to referto other hardware capable of performing such functions and/or executingsoftware, such as the example hardware recited above.

The functions of the various elements including functional blocks,including but not limited to those labeled or described as “computer”,“processor” or “controller”, may be provided through the use of hardwaresuch as circuit hardware and/or hardware capable of executing softwarein the form of coded instructions stored on computer readable medium.Thus, such functions and illustrated functional blocks are to beunderstood as being either hardware-implemented and/orcomputer-implemented, and thus machine-implemented.

Nodes that communicate using the air interface also have suitable radiocommunications circuitry. Moreover, the technology can additionally beconsidered to be embodied entirely within any form of computer-readablememory, such as solid-state memory, magnetic disk, or optical diskcontaining an appropriate set of computer instructions that would causea processor to carry out the techniques described herein.

It will be appreciated that the technology disclosed herein is directedto solving radio communications-centric issues and is necessarily rootedin computer technology and overcomes problems specifically arising inradio communications. Moreover, in at least one of its aspects thetechnology disclosed herein improves the functioning of the basicfunction of a wireless terminal and/or node itself so that, for example,the wireless terminal and/or node can operate more effectively byprudent use of radio resources.

Although the description above contains many specificities, these shouldnot be construed as limiting the scope of the technology disclosedherein but as merely providing illustrations of some of the presentlypreferred embodiments of the technology disclosed herein. Thus the scopeof the technology disclosed herein should be determined by the appendedclaims and their legal equivalents. Therefore, it will be appreciatedthat the scope of the technology disclosed herein fully encompassesother embodiments which may become obvious to those skilled in the art,and that the scope of the technology disclosed herein is accordingly tobe limited by nothing other than the appended claims, in which referenceto an element in the singular is not intended to mean “one and only one”unless explicitly so stated, but rather “one or more.” All structural,chemical, and functional equivalents to the elements of theabove-described preferred embodiment that are known to those of ordinaryskill in the art are expressly incorporated herein by reference and areintended to be encompassed by the present claims. Moreover, it is notnecessary for a device or method to address each and every problemsought to be solved by the technology disclosed herein, for it to beencompassed by the present claims. Furthermore, no element, component,or method step in the present disclosure is intended to be dedicated tothe public regardless of whether the element, component, or method stepis explicitly recited in the claims. No claim element herein is to beconstrued under the provisions of 35 U.S.C. 112, sixth paragraph, unlessthe element is expressly recited using the phrase “means for.”

What is claimed is:
 1. A user equipment that communicates over a radiointerface with a base station apparatus of a radio access network (RAN),the user equipment comprising: processor circuitry configured toinitiate a first type system information block (SIB) acquisition processto receive a first type SIB, the first type SIB comprising: schedulinginformation of a system information (SI) message, the SI messagecomprising at least one second type SIB; and an indication of broadcaststatus for the SI message, the indication indicating on-demand delivery;receiver circuitry configured to receive the first type SIB; andtransmitter circuitry configured to transmit an SI request message torequest the SI message; the processor circuitry further configured toinitiate an SI message acquisition process to receive the SI message;wherein in a case that a stored version of one of the at least onesecond type SIB is not valid, the first type SIB acquisition process isinitiated upon a failure of the SI message acquisition process.
 2. Theuser equipment of claim 1, wherein the processor circuitry is furtherconfigured to re-initiate the SI message acquisition process based onthe first type SIB acquisition process being initiated upon the failureof the SI message acquisition process.
 3. A method for a user equipmentthat communicates over a radio interface with a base station apparatusof a radio access network (RAN), the method comprising: initiating afirst type system information block (SIB) acquisition process to receivea first type SIB, the first type SIB comprising: scheduling informationof a system information (SI) message, the SI message comprising at leastone second type SIB; and an indication of broadcast status for the SImessage, the indication indicating on-demand delivery; receiving thefirst type SIB; transmitting an SI request message to request the SImessage; and initiating an SI message acquisition process to receive theSI message; wherein in a case that a stored version of one of the atleast one second type SIB is not valid, the first type SIB acquisitionprocess is initiated upon a failure of the SI message acquisitionprocess.
 4. The method of claim 3, further comprising re-initiating theSI message acquisition process based on the first type SIB acquisitionprocess being initiated upon the failure of the SI message acquisitionprocess.
 5. A base station apparatus of a radio access network (RAN)that communicates over a radio interface with a user equipment, the basestation apparatus comprising: transmitter circuitry configured totransmit first type system information block (SIB), the first type SIBcomprising: scheduling information of a system information (SI) message,the SI message comprising at least one second type SIB; and anindication of broadcast status for the SI message, the indicationindicating on-demand delivery; receiver circuitry configured to receivean SI request message to request the SI message; processor circuitryconfigured to use the transmitter circuitry to deliver the SI message;wherein the first type SIB is re-acquired by the user equipment upon theuser equipment failing on an SI message acquisition process to receivethe SI message, in a case that a version of one of the at least onesecond type SIB stored in the user equipment is not valid.
 6. The basestation apparatus of claim 5, wherein the first type SIB re-acquired bythe user equipment is used by the user equipment to re-initiate the SImessage acquisition process.
 7. A method for a base station apparatus ofa radio access network (RAN) that communicates over a radio interfacewith a user equipment, comprising: transmitting first type systeminformation block (SIB), the first type SIB comprising: schedulinginformation of a system information (SI) message, the SI messagecomprising at least one second type SIB; and an indication of broadcaststatus for the second type SI message, the indication indicatingon-demand delivery; receiving an SI request message to request the SImessage; delivering the SI message; wherein the first type SIB isre-acquired by the user equipment upon the user equipment failing on anSI message acquisition process to receive the SI message, in a case thata version of one of the at least one second type SIB stored in the userequipment is not valid.
 8. The method of claim 7, wherein the first typeSIB re-acquired by the user equipment is used by the user equipment tore-initiate the SI message acquisition process.